Uneven concrete slab repair system and method

ABSTRACT

This invention is directed to a main beam having a distal end that contacts a high side of a slab to define a pivot point; an anchor removably attached to a low side of the slab; a coupling attached between the anchor and the main beam so that when a proximal end of the beam is raised, the low side of the slab is raised; a jack coupled to the distal end for raising the proximal end of the main beam; a void defined between the surface under the slab and a bottom side of the slab when the slab is raised; and, filler material inserted in the void so that when the filler supports the slab after the anchor and beam are removed resulting in an evened slab.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to a system and method for repairing concrete that has sunken or settled without requiring the replacement of the concrete slab.

2. Description of Related Art

Concrete slabs are used for any number of construction projects that include: building foundations, parking lots, roads, pool decks, walkways, sidewalks, tennis sports areas (such as tennis courts, basketball courts and handball courts), decks, flooring and the like. Typically, the concrete slab is placed over a prepared surface such as graded soil with a moisture barrier. The underlying graded soil (ground) provides support for the slab.

Overtime, however, the underlying ground can become uneven causing the slab to rise or uplift making the original surface uneven. Causes that undermine the integrity and evenness of the ground underneath include erosion, tree roots, the freeze/thaw cycles associated with the usual concrete expansion and contraction and shifting ground. Further, when the slab is uneven, it can create a tripping hazard which is particularly troublesome when the concrete slab is part of a pool deck.

Typically, when the concrete slab becomes uneven, the repair process was to remove the slab and re-pour a new concrete slab. This is a time consuming process and results in a slab being discolored compared to the remaining slabs; an undesirable consequence when the slab is a patio, pool deck and the like. There is also no guarantee that the new slab will not settle again.

There have been efforts made to repair existing unsettled and uneven slabs such as in U.S. Pat. No. 6,976,804 directed to a method of repairing a concrete slab by injecting lime sludge under pressure in the space between the lower surface of the damaged slab and the underlying ground. The sludge attempts to lift the slab and remaining spaces are filled with dried sand blown in under pressure. U.S. Pat. No. 4,962,913 provides for a device to realign sidewalk sections displaced by settling or root lifting by using a span and cross members attached to hooks for lifting the slab from its sides so that the ground support can be repaired. U.S. Pat. No. 4,982,930 is a similar device using a beam and hooks that engage the slab on its sides. U.S. Pat. No. 8,186,907 attempts to remedy the problem by using filling voids under the slab with compressed air and sand with the flow of the air and sand being adjustable. U.S. Pat. No. 7,461,997 is directed to a sidewalk lifting system using a cylindrical bore for creating a space under the slab where material can be inserted under the slab to attempt to level the slab.

The need for concrete repair is certainly not limited to sidewalks. Referring to FIG. 1A, you can see that there is a significant crack 10 in the concrete slab 12 causing the edges of the slab to be uneven in relation to adjoining slabs. This creates a dangerous environment, especially since it surrounds a pool. Another disadvantage is that lifting the slab by the ends is near impossible since the edges are adjacent to other concrete slabs as well as the pool itself. Inventions which inject air, sand and other materials under the slab using the pressure of the injected material to raise the slab run the risk of causing the injected material to be forced against the pools underground plumbing, pool wall/liner and damaging either or both.

Referring to FIG. 1B, the slab is under bricks that make up the front porch. Again, lifting the slab from the end is impossible as the exterior walls of the house interfere with the ability to grab the ends of the slab. FIG. 2B shows similar problem with the conventional technology in that the slab is adjacent to the exterior wall and the edge of the slab cannot be grasped. FIG. 2B shows concrete steps that are adjacent to the exterior wall making grabbing the sides difficult. Further, injected material under the steps is limited to the ability of the injected material not to be expelled from under the steps as the steps are not completely surrounded by supporting ground.

There is also a need to repair sideways, walkways, slabs and the like when a tree or other plant's root system creates unevenness in the slab. When the tree roots grow under a slab, the slab can be lifted creating an uneven and hazardous surface. Referring to FIG. 1C, the slab is shown lifted by the tree root 11 which has grown under the sidewalk. This creates an uneven surface on the sidewalk presenting a hazardous environment for walkers, riders and other using the sidewalk. Additionally, water can run under the slab further damaging the arrangement of the sidewalk.

According to one source, a method of resolving this issue is to cut the tree root system. However, this leads to tree instability, damages the tree and is only a short term problem as the roots grow back. Research at the Bartlett Tree Research Laboratories has demonstrated that cutting large lateral roots within the root plate, which is a distance from the trunk of three times the trunk diameter, can destabilize a tree. For example a 20-inch diameter tree should not have roots cut closer than 60 inches from the tree (3×20=60). In a 6-foot wide swale with a growing tree, that does not allow space to root prune at the edge of the sidewalk. This source concluded that root pruning should only be done as a last resort when all other methods have been judged as not feasible. Other methods such as shaving the concrete, slabjacking, excavation, thicker concrete and meandering sidewalks each have their disadvantages. For example, shaving the concrete reduces the strength leaving the slab prone to damage such as cracking.

Therefore, it is an object of this invention to provide for a system and method for leveling concrete slabs where the supporting ground does not completely surround the slab and the slab cannot be raised by its edge based upon the environment where it is installed.

It is another object of the present invention to provide for a system and method for leveling concrete slabs where roots are disposed under the slab.

SUMMARY OF THE INVENTION

The objectives of this invention are accomplished by providing a concrete slab repair system and soil stabilization method comprising: a main beam having a distal end that contacts a high side of a slab to define a pivot point; an anchor removably attached to a low side of the slab; a coupling attached between the anchor and the main beam so that when a proximal end of the beam is raised, the low side of the slab is raised; a jack coupled to the distal end for raising the proximal end of the main beam; a void defined between the surface under the slab and a bottom side of the slab when the slab is raised; and, filler material inserted in the void so that when the filler supports the slab after the anchor and beam are removed resulting in an evened slab.

The invention can include a system for repairing uneven slabs comprising: a main beam having a proximal end and a distal end; a first anchor removably attached to a low side of the slab; a first coupling assembly removably attached between the proximal end of the main beam and the first anchor; a second anchor removably attached to a high side of the slab; a second coupling assembly removably attached between the distal end of the main beam and the second anchor; a first jack carried by the proximal end of the main beam and a second jack carried by the distal end of the main beam; a void defined between the surface under the slab and a bottom side of the slab when the slab is raised; and, filler material inserted in the void so that the filler material supports the slab after the anchor, coupling assembly and main beam are removed.

The invention can also include a hook that attaches to the anchor, notches defined in a top surface of the main beam to prevent the coupling from sliding toward the distal end when the system is in use, a securing member to secure the coupling at a fixed position along the main beam and hand openings defined in the proximal and distal ends of the main beam to allow for carrying the main beam.

The invention can include an injection opening defined in the slab for injecting filler material, a buffer pad disposed under the distal end of the main beam to dissipate force exerted by the main beam over a larger area and lateral beams included in the main beam; an opening defined between the lateral beams; and, a stop disposed in the opening that protrudes above the lateral beam and contacts the coupling to prevent the coupling from sliding toward the distal end. Cross members can be attached between the lateral beams. The filler material forms a plurality of columns between the ground and the slab so that the filler material does not contiguously fill the void. This results in a pier arrangement. The main beam includes a first beam and a second beam in an offset configuration joined by an extension coupling to provide a span longer than either beam individually. The extension coupling includes an extension securing member to secure the extension coupling to the first and second beams.

DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood by referencing the following drawings:

FIGS. 1A through 1C illustrate some of the issues addressed by the invention;

FIGS. 2A and 2B show a side view of aspects of the invention;

FIGS. 3A and 3B show a side view of aspects of the invention;

FIG. 3C shows a side view of aspects of the invention;

FIGS. 4A and 4B show a side view of aspects of the invention;

FIGS. 5A and 5C show perspective views of aspects of the invention;

FIGS. 6A and 6B show perspective views of aspects of the invention;

FIG. 7 is a top view of aspects of the invention; and,

FIG. 8 is a side view of aspects of the invention.

DESCRIPTION OF THE INVENTION

Referring to FIG. 2A, a first concrete slab 20 is shown level and in its proper position. The ground 22 underneath supports the slab. Over time, erosion or other causes, creates a void 24 under uneven slab 26 or otherwise undermines the supporting ground causing slab 26 to be uneven in relation to the adjacent slab 20 and slab 28. The uneven slab includes a high side 30 and a low side 32 when it is uneven. Therefore, to remedy the uneven slab, it is desirable to raise the low side while the high side lowers back to an even position in relation to adjacent slabs.

In one embodiment, a main beam 34 is attached to the low side of the uneven slab. The beam can be wood, metal or composite. The beam can be attached by securing an anchor 36 into the low side of the beam. The beam can include notches 76 that allow the coupling to be positioned along the beam and assist in preventing the coupling from sliding along the beam. Hand hold opening 77 can be defined in the distal and proximal ends of the beam for assisting the transportation of the beams to and from the operational location. A lifting bolt 38 can be secured to the anchor allowing for the slab to be lifted by applying upward force on the lifting bolt. The lifting bolt can be attached to a proximal end 40 of the beam through such as with a coupling 42. A securing member, such as square rod 44 which lies across the top of the beam, can prevent the coupling from slipping when an upward force is placed on the proximal end of the beam. The coupling can be a chain with a clevis hook 41 in one embodiment. In one embodiment the coupling assembly can include the coupling, hook and chain or variations and substitutions thereof.

In one embodiment, the distal end 46 of the beam is disposed on the high side of the uneven slab and distal surface 48 contacts the top of the slab. Jack 50 can be removably attached to the proximal end of the beam so that when a jack crank arm 52 is rotated, the jack causes the proximal end of the beam to move upward in direction 54. In one embodiment, the jack is a rotational crank, vertical crank, hydraulic, pneumatic,

The jack can include a base 51 that distributes force on the slab. One advantage to a hand crank is that the operator receives tactile feedback as to the tension to be applied, and can adjust the rate of rise on the slab reducing the chance of damaging the slab when lifting the lower end. When the proximal end is raised, the distal end applies force to the high end of the slab forcing it downward.

In one embodiment, once the slab is maneuvered into an even orientation as shown in FIG. 2B, the raised slab is lowered approximately 1/8″. The void under the slab is now ready to be filled, and the soil under the slab is stabilized. An injection hole 58 is drilled in the slab to a defined opening which allows for filler material to be inserted under the slab and into the void. As the slab is being supported by the beam, the filler material flows to areas of least resistance (and in a path that the operator has more control) to much more evenly fill the void. In the prior technology, the filler material is used to force the slab upwards which resulted in less predictable movement of material as the slab position moved from uneven to even, providing a less desirable foundation for the slab. By lowering the slab 1/8″ and using the filler material to ‘re-lift’ the slab back to level, the filler material is pushed into the supporting substrate in a less aggressive manner but still achieves sufficient soil stabilization.

This is advantageous in situation such as shown in FIGS. 5A and 5B when it is not desirable for filler material to run out of the crack and into the pool. Filler material can include mud, sand, polyurethane and epoxy. In one embodiment, the polyurethane is an expanding foam.

Referring to FIG. 3A, the distal end of the beam contacts the adjacent concrete slab 28, rather than the uneven slab. Therefore the pivot point of the beam is shown as 60. In this embodiment, the slab, when the proximal end of the beam is raised, can pivot at a point where the uneven slab contacts the supporting ground such as at 62. Once the proximal end has been sufficiently raised, the slab is leveled as shown in FIG. 3B. The filler material can be injected into the opening once the slab is leveled thereby removing the requirement that the injected material itself must be used to maneuver the slab to an even position.

In one embodiment shown in FIG. 3C, a buffer pad 64 can be placed between the distal end of the beam and the slab (uneven slab or adjacent slab) to distribute the force applied to the distal end over a larger surface of the slab and reduce potential damage to the slab by the main beam and lifting process.

In one embodiment shown in FIGS. 4A and 4B, the two jacks 50 and 50 a can be used. The beam is attached to a jack at its proximal end and at its distal end. The beam is attached to the slab through a first anchor and lifting bolt 114 a and a second anchor and lifting bolt 114 b. When the jacks apply upward force on the slab, it is held above the ground and the void can be filled with filler material. Referring to FIG. 4B, in one embodiment, the filler material can be an expansion foam that is deposited under the raised slab through tube 100. The tube can be used to place a finite amount of filler material under the slab in an amount that prevents the filler material from expanding to the edge of the slab. The filler material 102 d and 102 b can then be allowed to cure resulting in a column of filler material that supports the slab at various locations under the slab. This technique reduces the amount of filler material used, thus reducing costs, and also prevents the filler material from seeping from under the slab thereby reducing or eliminating clean up of excess filler material. In one embodiment, the filler material is filler is deposited under the raised slab through a series of short injections with long period between injections. These techniques allow the foam to partially solidify and form supportive piers 102 d and 102 b at various locations under the slab.

Referring to FIGS. 5A and 5B, the invention is shown in one embodiment in operation. The uneven slab 12 is adjacent to the pool with the high side at the pool edge and the low side disposed away from the pool near the fencing. A first beam 34 a has its distal end supported by a buffer pad 64 a. Beams 34 b through 34 e are also secured to the concrete slab through lifting bolts attached to the slab. When the jack raises the proximal end, the slab is forced upwards at the lower end and the higher end is forced downward. The filler material can then be inserted into the opening so that it flows into the void spaces without excessive flow towards the pool or downward which can damage underground plumbing. Multiple beams can be used in multiple configurations. For example, beam 34 b has a distal edge pressed against the edge of the slab adjacent to the pool so that this edge remains properly positioned when the remaining beams area raised.

In one embodiment, the coupling can be a chain as shown in FIG. 5B. This chain is wrapped around the main beam. The main beam is comprised of two laterally spaced beams 110 a and 110 b defining an opening 108 between the lateral beams. A stop 106 can be secured in the opening so that the stop protrudes above the lateral beams. The coupling then contacts the stop to prevent the coupling from sliding down the beams toward the distal end.

Referring to FIG. 5C, beam 34 is a slip beam configuration so that a slot 70 is defined by two side members 35 a and 35 b included in the beam. The jack is positioned in the slot and can include support surfaces 72 a and 72 b (FIG. 7) so that the beam is lifted by the jack. Cross members 74 can be included in the beam for structural support. Referring to FIG. 7, the top of one embodiment of the beam is shown. Side members 35 a and 35 b are connected by cross members 74 forming the beam. Support surfaces 72 a and 72 b contact the beam so that when the support surfaces are raised, the beam is raised. Opening 70 can receive the jack and couplings which can be positioned where needed all along the length of the beam.

Referring to FIGS. 6A and 6B, one embodiment is shown that can be used to create a bridge over an undesirable interfering structure such as a tree root 11. Slab 20 is lifted so that the adjacent edges to slabs 20 and 28 are even. When a tree root has grown under the slabs, the slabs may have to be slightly elevated to create a bridge over the root. Once the slab is lifted and properly positioned, a void is created under the slab that can receive filler material. The filler material can be deposited under the slab at the edges or through filler openings such as shown as 104 a and 104 b. The filler material can be placed under the slab, such as by using hose 100, in areas and in discrete areas under the slab. When the filler material cures, the filler material creates a column that provides support between the ground and the slab. Multiple columns 104 a through 104 d can be formed through multiple applications of filler material so that the filler material supports the slab without being contiguously applied under the slab.

Referring to FIG. 8, an extension coupling 78 is shown with an opening 82 defined in the arms of the extension coupling for receiving an extension securing member 80. In configuration 84, two beams are disposed offset and secured together with extension coupling to provide a span of 86 using the two beams which is longer than any one beam. This configuration allows for modifying the beam to operational length 86 while reducing the number of varying sizes needed. The invention can be transported in a cart where a plurality of different beams can be carted to the operational location. The beams can be the same or differing length.

In operation, the following steps are taken to remedy an uneven slab using the present invention (the following steps do not necessarily need to preformed in the same order in which they are presented):

a. An anchor opening is drilled into the concrete slab at the low end of the slab. In some cases, multiple holes will be drilled for multiple anchors based upon the geometry of the slab, its orientation and its location. For example, a long slab comprising the edge of a pool with a low side away from the edge may require several anchors at the low end so that it can be supported at multiple locations;

b. An injection opening is drilled into the slab to allow for filler material to be injected under the slab once the slab is raised. When the slab is raised, the void under the slab is shaped so that when filled by the filler material, the void need not change geometry to force the slab upwards;

c. A jack is placed at the low end of the slab on a surface adjacent to the edge of the uneven slab;

d. A beam is placed on the jack and supported by the jack so that the proximal end will raise and lower as the jack is raised and lowered. The distal end is placed on the high end of the uneven slab, on a surface adjacent to the high end of the slab or a second jack that is placed on a surface adjacent to the high end of the slab.

e. A coupling is attached to an anchor attached to the low end of the slab and also attached to the beam using a square rod inserted through the coupling wherein the rod can rest on top of beam.

f. The jack is slowly raised resulting in an upward force on the coupling which in turn raises the low end of the slab in relation with the adjacent slabs or surfaces. The high end is lowered as the low end is raised which positions the slab in an even position. Then the ends are lowered slightly;

g. Filler material is then injected into the opening of the slab so that filler material flows into the void defined by the now evened slab and the support ground. As the slab is supported, the filler material will properly flow to fill the void without the slab shifting or otherwise being forced into different positions increased by the ability of the filler material. As the slab edges are lifted back up to level with adjacent slabs, the soil is also stabilized by the material, again in a non aggressive manner. In industrial applications where heavy vehicle traffic is expected, more aggressive soil stabilization techniques are used. In one embodiment, the filler material is applied by: (i) inserting a portion of filler material in a discrete area under the slab in a volume insufficient to completely fill the void under the slab; (ii) waiting for the filler material to cure; (iii) inserting a second portion of filler material in a second discrete area under the slab in a volume insufficient to completely fill the void under the slab; (iv) waiting for the second portion of filler material to cure so that column like supports are provided under the slab without the filler material completely filling the void defined between the slab and ground.

h. The coupling is then disconnected from the anchor. The coupling, lifting bolt (eyebolt in one embodiment), anchor, beam and jack are then removed. The remaining openings in the slab can be filled and the slab sanded to smooth the filling of the openings.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A system for repairing uneven slabs comprising: a main beam having a distal end that contacts a high side of a slab to define a pivot point; an anchor removably attached to a low side of the slab; a coupling attached between the anchor and the main beam so that when a proximal end of the beam is raised, the low side of the slab is raised; a jack coupled to the distal end for raising the proximal end of the main beam; a void defined between the surface under the slab and a bottom side of the slab when the slab is raised; and, filler material inserted in the void so that when the filler supports the slab after the anchor and beam are removed resulting in an evened slab.
 2. The system of claim 1 wherein the coupling includes a hook that attaches to the anchor.
 3. The system of claim 1 wherein the main beam includes notches defined in a top surface of the main beam to prevent the coupling from sliding toward the distal end when the system is in use.
 4. The system of claim 1 including a securing member to secure the coupling at a fixed position along the main beam.
 5. The system of claim 1 including hand openings defined in the proximal and distal ends of the main beam to allow for carrying the main beam.
 6. The system of claim 1 including an injection opening defined in the slab for injecting filler material.
 7. The system of claim 1 including a buffer pad disposed under the distal end of the main beam to dissipate force exerted by the main beam over a larger area.
 8. The system of claim 1 including: lateral beams included in the main beam; an opening defined between the lateral beams; and, a stop disposed in the opening that protrudes above the lateral beam and contacts the coupling to prevent the coupling from sliding toward the distal end.
 9. The system of claim 8 including cross members attached between the lateral beams.
 10. The system of claim 1 wherein the filler material forms a plurality of columns between the ground and the slab so that the filler material does not contiguously fill the void.
 11. The system of claim 1 wherein the main beam includes a first beam and a second beam in an offset configuration joined by an extension coupling to provide a span longer than either beam individually.
 12. The system of claim 11 wherein the extension coupling includes an extension securing member to secure the extension coupling to the first and second beams.
 13. A system for repairing uneven slabs comprising: a main beam having a proximal end and a distal end; a first anchor removably attached to a low side of the slab; a first coupling assembly removably attached between the proximal end of the main beam and the first anchor; a second anchor removably attached to a high side of the slab; a second coupling assembly removably attached between the distal end of the main beam and the second anchor; a first jack carried by the proximal end of the main beam and a second jack carried by the distal end of the main beam; a void defined between the surface under the slab and a bottom side of the slab when the slab is raised; and, filler material inserted in the void so that the filler material supports the slab after the anchor, coupling assembly and main beam are removed.
 14. The system of claim 13 wherein the main beam includes a first beam and a second beam in an offset configuration joined by an extension coupling to provide a span longer than either beam individually.
 15. The system of claim 13 including: lateral beams included in the main beam; an opening defined between the lateral beams; and, a stop disposed in the opening that protrudes above the lateral beam to prevent the coupling from sliding toward the distal end.
 16. A system for repairing uneven slabs comprising: attaching an anchor to a low end of a slab; attaching a coupling included in a coupling assembly connecting the anchor and a main beam; raising a proximal end of the main beam so that the low side of the slab is raised to create a void between the surface under the slab and a bottom side of the slab; inserting filler material in the void so that the filler supports the slab; and, removing the anchor, coupling assembly and main beam.
 17. The system of claim 16 wherein the step of inserting filler material includes inserting filler material in an area less than the area defined by the void so that the filler material forms a column between the ground and slab so that the filler material does not contiguously fill the void.
 18. The system of claim 16 including: inserting filler material for a predetermined period of time; and, waiting a longer period of time that the predetermined period of time so that the filler material forms a column between the ground and slab so that the filler material does not contiguously fill the void.
 19. The system of claim 16 including the step of placing a distal end of the main beam on a high end of the slab to create a pivot point.
 20. The system of claim 19 including the step of placing a buffer pad under the distal end of the main beam to dissipate force exerted on the slab from the main beam over a larger area. 